Various disk-shaped data storage media are used extensively today. Examples of data storage media for performing read and/or write operations with a light beam include CDs, DVDs, and DVD-RAMs. On the other hand, a floppy disk is a data storage medium for performing read and/or write operations with magnetism. Furthermore, MOs and MDs for performing read and/or write operations with both a light beam and magnetism have also become popular.
Among these disk-shaped data storage media, DVD-RAMs, MOs and so on are contained in a cartridge for the purpose of protecting the data storage layer thereof. Japanese Patent Application Laid-Open Publication No. 9-153264 discloses a cartridge such as that shown in FIG. 10 as such a cartridge.
The disk cartridge 100 includes a cartridge body 101 for containing a writable/readable disk 102 and a shutter 103. A window 101A for getting the disk 102 chucked and allowing a read/write head to access the disk 102 is provided on both sides of the cartridge body 101. The shutter 103 protects the disk 102 that is exposed through the window 101A. For that purpose, the shutter 103 has a square bottomed U-shape. The shutter 103 is supported on the cartridge body 101 so as to be movable in the direction pointed by the arrow P, and elastic force is applied from a spring (not shown) to the shutter 103 in the opposite direction to that pointed by the arrow P. Accordingly, while no external force is applied to the shutter 103, the window 101A is closed with the shutter 103.
As shown in FIG. 7, a disk drive, adapted to the disk cartridge 100, includes a shutter opener 104 for opening and closing the shutter 103. When the disk cartridge 100 containing the disk 102 is loaded into the disk drive to read and/or write data from/on the disk 102, the disk cartridge 100 is inserted in the direction pointed by the arrow Q. Then, the notched portion 103A of the shutter 103 gets engaged with the protrusion 104A of the shutter opener 104. As the disk cartridge 100 is inserted deeper, the shutter opener 104 turns around the center of rotation 104B in the direction pointed by the arrow R. As a result, the shutter 103, engaged with the shutter opener 104, moves in the direction pointed by the arrow P.
When the disk cartridge 100 is inserted fully, the shutter 103 will have completed its movement in the direction pointed by the arrow P. Consequently, the disk 102 is exposed through the window 101A.
In the disk cartridge 100 shown in FIG. 10, the shutter 103 has a square bottomed U-shape with a flat bottom as described above. However, a shutter with such a shape requires a highly sophisticated machining technique. Also, to keep the shutter 103 in shape constantly, the machining process must be carried out with high precision. Thus, the cost for the shutter 103 as a single part is so high as to raise the overall manufacturing cost of the disk cartridge 100 significantly. Furthermore, the shutter structure described above cannot contribute to reducing the thickness of the disk cartridge 100 effectively. Consequently, with such a shutter structure, it is difficult to fill the consumers' demand for smaller storage media, which is also a problem.
In addition, considering the structure of the shutter 103, a gap is easily created between the cartridge body 101 and the shutter 103. Thus, dust and dirt may enter the disk cartridge and affect the read and/or write operations.
Plus, the disk drive described above opens the shutter 103 while the disk cartridge is being loaded. Accordingly, while being loaded into the disk drive, the disk 100 is partially exposed through the window 101A. Consequently, dust or dirt may deposit on the disk 100 to possibly affect the read and/or write operation on the disk 102.
To overcome these problems, Japanese Patent Application Laid-Open Publication No. 2002-50148 (and its corresponding U.S. Pat. No. 6,590,858) discloses a disk cartridge including a plurality of flat-plate shutters. As shown in FIG. 11, the disk cartridge 200 includes a cartridge body 201, shutters 202 and 203, and a rotational member 204. Although the body of the disk cartridge 200 actually consists of an upper shell and a lower shell, the upper shell is not shown in FIG. 11.
The cartridge body 201 has a window 201C for getting the disk chucked and allowing a read/write head to access the disk 205. While no chucking or head access is needed, the window 201C is closed with the shutters 202 and 203. The shutters 202 and 203 are interlocked with, and opened and closed by, the rotational member 204. The rotational member 204 rotates around a point that substantially matches the center of the disk 205 stored. The rotational member 204 also has a window 204G that has almost the same shape, and will be located at substantially the same position, as the window 201C when the shutters 202 and 203 open the window 201C fully.
A pair of link spindles 201A and 201B is additionally provided for the cartridge body 201 so as to be inserted into the link grooves 202B and 203B of the shutters 202 and 203, respectively.
Also, the rotation holes 202A and 203A of the shutters 202 and 203 are fitted with the rotation shafts 204A and 204B of the rotational member 204, thereby securing the shutters 202 and 203 to the rotational member 204 in a rotatable position.
FIGS. 12 to 14 illustrate how the rotational member 204 and the shutters 202 and 203 operate in the disk cartridge 200.
FIG. 12 illustrates a situation where the shutters are closed. In this situation, if the rotational member 204 is rotated in the direction pointed by the arrow S, then the rotation shafts 204A and 204B and the rotation holes 202A and 203A will turn in the directions pointed by the arrows T1 and U1, respectively. In the meantime, the link grooves 202B and 203B slide along the link spindles 201A and 201B in the directions pointed by the arrows T2 and U2, respectively.
If the rotational member 204 is further rotated in the arrow direction S, the shutters 202 and 203 start to open themselves as shown in FIG. 13. When the rotational member 204 is rotated to the limit, the shutters 202 and 203 will be fully opened as shown in FIG. 14. At this point in time, the windows 201C and 204G substantially match each other, thereby getting the disk 205, stored in the disk cartridge, ready to be chucked and the read/write head (not shown) ready to access the disk.
To close the shutters and the window 201C, the rotational member 204 needs to be rotated in the opposite direction to that pointed by the arrow S such that the rotational member 204 and the shutters 202 and 203 will do the opposite operations.
In order to open and close the shutters this way with good stability, the disk cartridge needs to be held firmly. To allow the disk cartridge 200 to perform the above operations within the disk drive, the side surfaces of the disk cartridge 200 are preferably held by holding members 211L and 211R as shown in FIGS. 12 to 14.
According to Japanese Patent Application Laid-Open Publication No. 2002-50148, a first notch 204D, a gear portion 204E and a second notch 204F, provided for the rotational member 204, and the shutter driving means 250 shown in FIG. 15 are used to rotate the rotational member 204 in the disk drive. The shutter driving means 250 includes a first raised portion 251, a rack portion 252 and a first raised portion 253. By shifting the shutter driving means 250 parallel to the side surface of the disk cartridge 200, the first raised portion 251, rack portion 252 and second raised portion 253 get engaged with the first notch 204D, gear portion 204E and second notch 204F, respectively, thereby rotating the rotational member 204.
However, to slide the bar driving means 250 shown in FIG. 15 near the side surface of the disk cartridge 200, there should be a space for allowing the driving means 250 to move in the vicinity of that side surface of the disk cartridge. Then, it is difficult to provide the holding member 211R described above. Consequently, the disk cartridge 200 could not be held firmly or the driving means 250 and the rotational member 204 could not get engaged with each other as intended.